In This Chapter

table of contents

It's no secret that Maya is particularly suited to character animation ” characters such as Stuart Little and Aki from the Final Fantasy film have cemented Maya's reputation for 3D character animation. Maya offers powerful and rich tools to animate characters in virtually any way desired. With this versatility and power comes a great deal of complexity.

Early animation tools didn't offer skeletons and skeletal deformation. All animation had to use simple rotations , so all the characters had doll-like arms and legs with ball sockets where they connected. Naturally, it wasn't long before animators wanted to animate something softer than an exoskeletal cockroach. The general approach is to create a continuous outer skin for a character that follows the outer surface ”whether face, shoes, or shirt. Next , a set of linked joints are constructed and placed inside the character, similar to the armatures that claymation animators put in their characters. Finally, the joints are connected to the character mesh in a process known as skinning . By default, many of the joints will not bend "naturally" as we would like, so the animator must modify how joints bend the skin at each local trouble spot. Skinning a complex character so that it has a full range of natural motion can take several days. When complete, the bones bend within the character to deform its skin and clothes in a natural way ”a perfect analogy to regular flesh-and-blood animals.

To make character animation focused and straightforward, large firms employ specialists known as technical directors to add handles, menus , dialogs, movement constraints, and other tools for a character. This process, often called "rigging," will make the character animation process straightforward, as the character behaves by default the way the animator wants; for example, knees bend forward and not backward.

Character rigging is a complex subject, by itself worthy of a book. But this chapter will cover some straightforward approaches to let you learn the basics.

In this chapter, we show you the basics of each of the major elements of character animation. Maya offers many ways to solve each task, but we'll pick the most mainstream methods for our tutorials to get you started, while still mentioning the others so you know where to explore next.

Here are some of the concepts and techniques covered in this chapter:

  • Creating skeletons You can build, link, and edit collections of joints to make a skeleton for any type of creature.

  • Creating Inverse Kinematics Easy animation is possible through Inverse Kinematics, where joints automatically rotate in response to moving an IK handle to the end of the joint chain.

  • Skinning The skeleton deforms the character geometry after applying the character geometry to the skeleton in a process known as skinning .

  • Character rigging Adding easily selected items for control of the character will make it much quicker to animate.

  • Adding flexors Rigidly bound skeletons require a special deformer called a flexor to modify the way the skin bends around joints.

  • AutoKey A way to create animation keys automatically.

  • Trax A tool to work with animation as "clips" and shuffle them on a timeline.

  • Blend Shapes A deformer that lets you blend the shape of one surface into the shape of another surface or surfaces.

Key Terms

Skinning A kind of deformer that causes a polygonal or NURBS mesh to bend based on joints.

Skeleton A combination of connected joints.

Joint The pivot points of a skeleton.

Root Joint The base joint of a skeleton

Joint Chain Connected pivot points of a skeleton.

Forward Kinematics In linked hierarchies, rotating joints starting at the root joint to the last joint to reach a specific pose. For example, you might pose a character's torso, then bicep, then forearm, then hand to have the character reach upward. Often abbreviated to "FK."

Inverse Kinematics In linked hierarchies, moving the last joint (actually a "handle" at the end joint created for Inverse Kinematics) to cause all the in-between joints to be automatically rotated to reach a specific pose. For example, you would move a character's hand, and the forearm, bicep, and torso would adjust within defined constraints to "reach" wherever the hand was placed. Often abbreviated to "IK."

End Effector When IK is applied in Maya, a special controller is created with handles at each end. The end that manipulates the IK chain is called the end effector .

Bind Pose The position of the skeleton when it is bound to the skin; generally a neutral pose with limbs spread to facilitate skinning.

Clip A defined set of animation for use in Trax.

Blend Shape A deformer that allows you to assign other surfaces to the current surface as targets to be blended into. The Blend Shape deformer creates a special dialog with sliders, which are used to blend the base shape into one of the targets. This technique, known in other 3D packages as "morphing," is a popular way to animate facial expression or speech.

Hotkeys to Memorize

y Repeat the use of the last tool ”also known as the "non-sacred tool"

p Parent all selected objects to the last selected object

k + MMB -drag Scrub Time Slider



Maya 4. 5 Fundamentals
Maya 4.5 Fundamentals
ISBN: 0735713278
EAN: 2147483647
Year: 2005
Pages: 201

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